ROAR is announcing new battery approval procedures that are less costly, and provide quicker access to the latest battery technology. Under the previous rules, batteries were only approved 4 times per year. This led to mostly manufacturers complaining about one another using “illegal” batteries that were not approved before the previous deadline. The new process allows for approval as soon as a new battery is available, which eliminates the motivation to use, or assume that others are using, illegal cells. The new procedures will provide more level competition and equal access to racers beyond the factory teams. Any new battery manufacturer receiving an approval in close proximity to an event, will be required to have a limited number of the exact same batteries available for purchase, as a condition of the new rules. Below is the text of the refined battery approval process. Please take the time to review the new procedures and contact ROAR with any outstanding questions or concerns.
8.3 BATTERY RULES
8.3.1 General Battery Rules:
8.3.1.1 The approval of new battery types, makes, or capacities must be posted on the roarracing.com website. The Executive Committee has final approval over battery legality.
8.3.1.2 Only manufacturers, distributors, or resellers may submit batteries for approval. All batteries must be submitted by ROAR industry affiliates.
Battery Approvals
8.3.1.3 Battery approvals will be processed upon submission. The submission date will be defined as the day AFTER the samples are received by the ROAR battery lab. All unique samples will require full completion of the approval request form available on the roarracing.com website under the “Approvals” link. Samples must be sent via couriers that provide accurate and accessible tracking data via the internet.
The standard approval process for batteries submitted by a manufacturer or exclusive US distributor will require two sample battery packs of each type seeking approval, to be received at least three FULL weeks prior to the desired approval date(not counting the day of receipt), such as an event, for example. The approval fee for new batteries will be $100 for each unique battery type submitted. An expedited approval may also be available. If a new battery is submitted less than 3 weeks prior to the desired approval date, a fee of $200 will be required (NO exceptions!) for each unique battery, and no guarantees with ROAR can be made regarding the ability to complete the approval by the desired date. The manufacturer or distributor must make separate arrangements directly with the independent battery lab to determine the likelihood of completing the approval in an expedited scenario. Regardless, no refunds will be available in the event the approval(s) is not completed by the desired date.
Under no circumstances will an approval be accepted less than three FULL days prior to the start of a ROAR Sanctioned event (not including the day of receipt). The start of an event will be defined as the first day of open practice. Manufacturers, distributors and retailers who obtain an approval less than three weeks prior to the event will be required to have at least 30 packs available for sale through a trackside or nearby affiliated hobby shop, or via direct sales, without prejudice to any prospective buyers (competitors, etc.).
8.3.1.4 Secondary Approvals
Resellers desiring approval for the EXACT same battery from a manufacturer or distributor that has already received approval, may simply submit a sample for a secondary approval under their own trademarked name only under the following conditions:
• You must have the written permission of the manufacturer or distributor that received the original approval (verification must be received by Battery Lab and at least the ROAR President and/or Technical Director by mail or email from the company principle) within the aforementioned timeframes.
• One pack must be submitted within three FULL weeks prior to the start of an event. Resellers that submit batteries in less than three FULL weeks prior to the desired approval date, will need to provide the same quantities available for sale under the requirements as outlined for a manufacturer/distributor in rule 8.3.1.3.
• The reference pack(s) is submitted exactly as it will be sold, including all the proper labeling and ROAR mandated tamperproof seals.
• A complete Battery Approval Request form containing accurate information accompanies each battery seeking approval. The form is available on the roarracing.com website under the “Approvals” link.
• The interior cells and external label match the capacity and C-rating of the original approved battery, and the manufacturer’s name and internal serialized code matches that of the approved battery.
Assuming all of the aforementioned conditions are met, and the reseller accurately completes the Battery Approval Request Form, the battery will receive a secondary approval at no charge.
Secondary approvals are only valid as long as the primary approval is valid and is at the discretion of the holder of the original approval. If for certain reasons, a primary approval is invalidated, for a rules infraction for example, all secondary approvals may be invalidated. This is subject to the discretion of the ROAR President.
In the event an approval is abandon (e.g. dissolution of the agreement between manufacturer and distributor of a currently approved battery, loss of affiliate status, etc.), the approval will revert back to the original manufacturer or a new distributor, subject to the discretion of the ROAR President.
8.3.1.5 Labeling of batteries:
8.3.1.5.1 The battery’s foil seal must have indelible markings that include the original manufacturer’s name, the rated capacity of the cell, the CONSTANT “C” rating (clearly identified as “Constant”), and it must be serialized to distinguish different versions of cells from the manufacturer. The capacity and constant C rating must also be visible on the exterior battery label, identified as “XXXX mAh” where “XXXX” represents the capacity in milliamp hours, and “XXC Constant” where “XX” indicates the manufacturer-provided CONSTANT C-rating.
This accurate information is essential in determining safe charging and discharging practices based on acceptable and largely published norms for LiPo battery handling. The confusion with “Burst” or ambiguous C-ratings conflicts with accepted charging practices and may inadvertently create unsafe conditions. Higher “C” ratings imply higher potential charge/discharge rates, making the need for this standardized information essential for safe charging, use, discharging and storage of LiPo batteries. Additionally, confusion with Burst and Constant C-ratings might confuse the user into thinking they’re using a battery of adequate C-rating as required by the application, only to find out that their purchase was based on a Burst rating instead of a Constant rating. Confusion of this sort can cause rapid overheating and dangerous fire hazards, and it has no place in ROAR competition.
***The above section will not be enforced until the beginning of the Winter 2011/Fall 2012 electric racing season (Beginning October 1, 2011). This should provide manufacturers and retailers sufficient time to comply with these requirements.
ROAR makes no inference as to the burst ratings. Manufacturers are welcome to include any additional information beyond the basic requirements outlined above. The required information is essential, however, in determining if a LiPo battery is sufficient for its application, and in determining safe charge/discharge parameters for each battery. It simply MUST be provided.
8.3.1.5.2 Any indication that the original manufacturer-applied label has been changed or tampered with will make the LiPo battery pack illegal. Aftermarket wraps/decals MUST NOT replace the original label. Should the original label be removed, the product will be ruled an unapproved product which could subject the racer to disqualification.
8.3.1.6 If protested, it is the driver’s responsibility to prove the legality of his battery(s).
8.3.1.7 Batteries may not be recharged or changed during a standard length race. Batteries may only be changed during an Endurance race.
8.3.1.8 Unless otherwise specified in the class requirements, a maximum of a 2s 7.4v LiPo battery is permitted in any vehicle motor power pack used in ROAR-sanctioned competition.
8.3.1.9 Drivers are responsible for the proper disposal of batteries that are no longer useable. No batteries should be discarded in ordinary trash containers, and may not be abandoned at race sites. It is recommended that tracks promote safety and non-pollution by providing an approved disposal container for unusable batteries.
8.3.1.10 Running Change to Cell: Manufacturers that make a running change without re-submitting the item for Lab review will forfeit the approval of that product, and possibly all related products from the manufacturer for a period of time to be determined by ROAR. A new component (especially a different composition of cell) will need to be submitted for inspection/approval. The LiPo Approval Inspection includes specifications our Race Management Teams can confirm in the field. If during the race inspections, a pack appears outside the original parameters, the Racer/User could be subject to disqualification for using an altered product. Deliberate attempts to use products that are not approved may result in a disqualification of no more than one year for one or all of a manufacturer’s related products, at the discretion of the ROAR President and the Executive Committee.
8.3.2 Lithium Polymer Batteries (Li-Poly):
8.3.2.1 Lithium Polymer battery packs may be used to power electric racing cars if a Certification of Compliance has been received and accepted by ROAR from the manufacturers of the battery packs. The Certification of Compliance indicates that the Lithium Polymer cells internal to the battery packs have been tested in accordance with UN T1-T8, the United Nations Recommendations on the Transport of Dangerous Goods, Manual of Test and Criteria (ST/SG/AC.10.11/Rev.4) and passed the acceptance criteria. Certification of Compliance to these test requirements and acceptance criteria shall be provided by the Original Manufacturer of the batteries. The Certification of Compliance will apply to all Lithium-Polymer products from the Original Manufacturer and provided on a one time basis. The Certification of Compliance can be sent directly to ROAR by the Original Manufacturer or supplied to ROAR by the US based distributor of the batteries. A reseller seeking secondary approval must also provide ROAR a Statement of Origin identifying the original manufacturer of the cells used in the battery pack
8.3.2.2 Li-Poly battery packs must have a hard, protective case that surrounds the cell(s) in the racing application. A factory-encased hard shell pack is mandated for race durability reasons that stem from the vulnerability of LiPo cells to physical damage. Any physical distortion, denting or puncture to the cells may cause either an immediate or long term safety risk. A hard-cased pack reduces this risk significantly by protecting the cells from crash damage, battery ejection, and general wear and tear. ROAR defines the “hard case” as a case made of ABS or similar type material. The case shall consist of two (2) halves with each half being constructed from a single mold that is not easily pliable and retains it shape without any exterior or interior support. Both the top and bottom sections of the case must be secured together by glue, double-sided tape or heat seal with a label across the seam stating “ROAR Approved” in such a manner that separation of the case to remove or replace the cells will destroy the case and/or label and render it unusable in competition. The case must be installed by the manufacturer or distributor; no user installed cases are acceptable. The case will protect the cells from damage on all sides and will completely cover all cells having only openings for wire connections. Any modification to the factory approved hard case will make the pack ineligible for participation in ROAR events. Approved batteries will be required to have a label stating “ROAR Approved” across the seam. ROAR will have a grandfather clause until Jan 2009 for all approved cells at competition on the Label rule.
8.3.2.3 LiPo/LiFe case maximum dimensions:
8.3.2.3.1 The maximum 1s 3.7v brick/stick case:
Length: 93mm
Width: 47mm
Height: 18.5mm
8.3.2.3.2 The maximum 1s 3.7v saddle case:
Length:93mm to be measured as two packs end to end as a maximum
Width: 46mm
Height: 23mm
8.3.2.3.3 The maximum 2s 7.4v brick/stick case::
Length: 139mm
Width: 47mm
Height: 25.1mm
8.3.2.3.4 The maximum 2s 7.4v saddle case:
Length: 139mm to be measured as two packs end to end as a maximum
Width: 47mm
Height: 25.1mm
8.3.2.3.5 The maximum 3s 11.1v or 4s 14.8v brick/stick case :
Length: 165 mm
Width: 52mm
Height: 52mm
8.3.2.4 The battery pack shall have leads extending from the case for the positive and negative electrical connections using wire of adequate size to handle discharge rates acceptable to racing applications. Alternatively, the case shall have external connection points for these wires clearly marked positive and negative so the user can apply the lead wires. Markings on the case are required stating the rated voltage, capacity, and C-rating of the battery. The distributor or reseller’s name and/or logo shall be easily readable on the case. Individual cells used in the construction of the battery shall be rated at 3.7v nominal. A 1s 3.7v nominal battery pack shall be 1 cell wired in series, a 2s 7.4v nominal battery pack shall be 2 cells in series, a 3s 11.1v nominal battery pack shall be 3 cells in series and a 4s 14.8v nominal battery pack shall be 4 cells in series. Multiple cells in parallel may be used.
8.3.2.5 Li-Poly Battery Charging and Discharging
8.3.2.5.1 Li-poly battery packs must be charged with chargers capable of the industry standard CC/CV (Constant Current/Constant Voltage) charge profile. No other charge profiles are permitted.
8.3.2.5.2 Li-Poly battery maximum charge voltage.
• 1s Li-Poly batteries may be charged to a maximum of 4.25v.
• 2s Li-Poly batteries may be charged to a maximum of 8.50v.
• 3s Li-Poly batteries may be charged to a maximum of 12.75v
• 4s Li-poly batteries may be charged to a maximum of 17.0v.
• 2S LiFe batteries may be charged to a maximum of 7.40v.
• There will be no allowances for overages.
8.3.2.5.3 Li-Poly battery maximum charge rate shall be 1C (actual rated capacity X 1) unless specifically authorized by the manufacturer to charge at a different rate. Charge amp rate = mAh capacity/1000=X amps, e.g. 5400 mAh = 5.4 amp charge rate.
8.3.2.5.4 The maximum temperature of a charged battery will be checked prior to each run, to not exceed 100°F (37.8°C), or ambient temperature + 5-percent, whichever is greater. The use of a battery warmer is permitted, but it may never exceed 100°F (37.8°C). Preheating of batteries is not permitted in ambient temperatures above 100°F (37.8°C).
8.3.2.5.5 Batteries must be charged with chargers that have balance ports, using only the balance mode for charging, or an acceptable alternative demonstrated to the satisfaction of the President and/or Technical Director. Charging without balance mode and without a balancing harness is not permitted. Simply connecting the harness and not using the balance mode is cause for disqualification. Only 1S 1P batteries may be charged without balancing, as it’s only one cell. Any packs consisting of 2P and/or 2S will require balanced charging or approved alternatives.
Balance charging ensures that each cell within the pack charges individually to full capacity. Non-balanced charging may inadvertently overcharge one cell, and undercharge the other. Under these conditions, the risk for battery failure is greater, or at least you will suffer from reduced performance.
8.3.2.5.6 The use of cooling device and or freeze sprays of any type to cool a li-poly battery is strictly prohibited.
8.3.2.5.7 Overcharging/Overheating, or practices that may result in the aforementioned, are defined as but not limited to the following:
• Charging of a li-poly battery with a charge profile other than CC/CV (i.e. NiCd/NiMH)
• Charging at a charge rate higher than 1C (in lieu of the manufacturer’s recommended charge rate)
• Charged battery voltage exceeding the max charge voltage per 8.3.2.5.2.
• Heating of the LiPo battery beyond the maximum allowable temperature, or the use of cooling devices to cool an overheated battery per 8.3.2.5.4., 8.3.2.5.5. and 8.3.2.5.6.
8.3.2.5.8 All LiPo batteries must be charged or discharged inside a “Lipo Sack” or similar fire mitigation device proven to withstand a minimum of a 8.4v 5000mAh for 2s, or 14.8v 5000 mAh for 4s packs. Simultaneous charging or discharging of LiPo battery packs requires a separate LiPo sack for each battery.
8.3.2.6 ROAR Impact/Drop Test:
8.3.2.6.1 The cells of the battery pack shall experience no loss of mass, no leakage, no venting, no rapid disassembly, and no rise in temperature. The case shall not splinter or shatter in a manner that would create shrapnel and potentially puncture the cell inside.
8.3.2.6.2 The fully charged battery pack shall be dropped from a height of 5 feet to a flat concrete floor. The battery pack shall land flat on the floor during the drop.
8.3.2.8.2 A 0.1 Ohm resistance shall be applied to a fully charged battery pack at room temperature (70 deg F +/-10). The test is concluded when the temperature of the battery pack returns to within10 deg of room temperature.
8.3.2.10 General Information About Li-Poly Batteries:
8.3.2.10.1 A LiPo battery pack can be damaged in many ways. The damage is cumulative and cannot be reversed. These rules provide the safest operation and longest pack life. Going outside these rules may result in a dangerous pack failure.
• Do not over discharge Lithium Polymer battery packs, and use a Proper ESC that features a lipo-specific voltage cutoff feature. Some newer ESCs give you the option to set a cutoff voltage, and some do not. Use the battery manufacturer’s recommended safe voltage cutoff.
• The maximum safe temperature of a Lithium Polymer pack is 140 degrees F.
• Only charge Lithium Polymer packs with a charger that is specifically compatible with LiPo batteries.
• Lithium Polymer packs that will not be run for more than a month or two, should be stored approximately half charged. Do not store them fully charged and do not store them fully discharged (6.0v or less) or damage will occur.
• External Thermal Damage – Temperatures above 60 deg C or 176 deg F are considered extremely dangerous for LiPo batteries. The thermal volatility is directly related to the cell chemistry used by the manufacturer.
• Overcharge – Lithium Polymer cells are extremely intolerant of an overcharge condition. It can consistently damage the cell(s) and create a fire risk.
• Over discharge – over discharging can destroy a cell. Don’t discharge a battery below its recommended voltage level, or store you cells completely discharged. It is strongly recommended that you disconnect the battery from all electronics since most have a small current drain even in the “off” position.
• External Short Circuit – Lithium Polymer batteries can deliver extreme amounts of current. In the case of a short circuit (positive lead touches negative lead), the rapid and powerful current drain will cause the battery to overheat with an extreme risk of fire.
• Internal Short Circuit – this is mostly caused by contaminants getting into the cell at the cell manufacturing level. Contaminants can poke through the separator over time causing an internal short. In most cases, this will cause the cell to expand (puff up). In extreme cases, this may be enough to ignite the cell. Every time you charge a cell with a micro short, the cell will expand about five-percent in thickness. Batteries with a visible bulge in the casing should be considered damaged and should not be used in competition. Contact the battery manufacturer to determine the best method of neutralizing the battery for disposal. NEVER discard a charged battery, damaged or not.
• External Mechanical Damage – A lithium polymer battery is made up of 20-30 layers of a very thin sheet copper anode, a thin plastic separator and a thin aluminum cathode. The vacuum sealed aluminum pouch keeps even pressure on the anode/cathode pairs. Even a small dent that results from a dropped tool can create a micro-short in an unprotected pack. This short will create heat that will cause the cell(s) to expand and develop into a possible fire hazard. This is why ROAR requires hard cases, which greatly minimize the chance of external mechanical damage to the cells.
8.3 BATTERY RULES
8.3.1 General Battery Rules:
8.3.1.1 The approval of new battery types, makes, or capacities must be posted on the roarracing.com website. The Executive Committee has final approval over battery legality.
8.3.1.2 Only manufacturers, distributors, or resellers may submit batteries for approval. All batteries must be submitted by ROAR industry affiliates.
Battery Approvals
8.3.1.3 Battery approvals will be processed upon submission. The submission date will be defined as the day AFTER the samples are received by the ROAR battery lab. All unique samples will require full completion of the approval request form available on the roarracing.com website under the “Approvals” link. Samples must be sent via couriers that provide accurate and accessible tracking data via the internet.
The standard approval process for batteries submitted by a manufacturer or exclusive US distributor will require two sample battery packs of each type seeking approval, to be received at least three FULL weeks prior to the desired approval date(not counting the day of receipt), such as an event, for example. The approval fee for new batteries will be $100 for each unique battery type submitted. An expedited approval may also be available. If a new battery is submitted less than 3 weeks prior to the desired approval date, a fee of $200 will be required (NO exceptions!) for each unique battery, and no guarantees with ROAR can be made regarding the ability to complete the approval by the desired date. The manufacturer or distributor must make separate arrangements directly with the independent battery lab to determine the likelihood of completing the approval in an expedited scenario. Regardless, no refunds will be available in the event the approval(s) is not completed by the desired date.
Under no circumstances will an approval be accepted less than three FULL days prior to the start of a ROAR Sanctioned event (not including the day of receipt). The start of an event will be defined as the first day of open practice. Manufacturers, distributors and retailers who obtain an approval less than three weeks prior to the event will be required to have at least 30 packs available for sale through a trackside or nearby affiliated hobby shop, or via direct sales, without prejudice to any prospective buyers (competitors, etc.).
8.3.1.4 Secondary Approvals
Resellers desiring approval for the EXACT same battery from a manufacturer or distributor that has already received approval, may simply submit a sample for a secondary approval under their own trademarked name only under the following conditions:
• You must have the written permission of the manufacturer or distributor that received the original approval (verification must be received by Battery Lab and at least the ROAR President and/or Technical Director by mail or email from the company principle) within the aforementioned timeframes.
• One pack must be submitted within three FULL weeks prior to the start of an event. Resellers that submit batteries in less than three FULL weeks prior to the desired approval date, will need to provide the same quantities available for sale under the requirements as outlined for a manufacturer/distributor in rule 8.3.1.3.
• The reference pack(s) is submitted exactly as it will be sold, including all the proper labeling and ROAR mandated tamperproof seals.
• A complete Battery Approval Request form containing accurate information accompanies each battery seeking approval. The form is available on the roarracing.com website under the “Approvals” link.
• The interior cells and external label match the capacity and C-rating of the original approved battery, and the manufacturer’s name and internal serialized code matches that of the approved battery.
Assuming all of the aforementioned conditions are met, and the reseller accurately completes the Battery Approval Request Form, the battery will receive a secondary approval at no charge.
Secondary approvals are only valid as long as the primary approval is valid and is at the discretion of the holder of the original approval. If for certain reasons, a primary approval is invalidated, for a rules infraction for example, all secondary approvals may be invalidated. This is subject to the discretion of the ROAR President.
In the event an approval is abandon (e.g. dissolution of the agreement between manufacturer and distributor of a currently approved battery, loss of affiliate status, etc.), the approval will revert back to the original manufacturer or a new distributor, subject to the discretion of the ROAR President.
8.3.1.5 Labeling of batteries:
8.3.1.5.1 The battery’s foil seal must have indelible markings that include the original manufacturer’s name, the rated capacity of the cell, the CONSTANT “C” rating (clearly identified as “Constant”), and it must be serialized to distinguish different versions of cells from the manufacturer. The capacity and constant C rating must also be visible on the exterior battery label, identified as “XXXX mAh” where “XXXX” represents the capacity in milliamp hours, and “XXC Constant” where “XX” indicates the manufacturer-provided C-rating.
This accurate information is essential in determining safe charging and discharging practices based on acceptable and largely published norms for LiPo battery handling. The confusion with “Burst” or ambiguous C-ratings conflicts with accepted charging practices and may inadvertently create unsafe conditions. Higher “C” ratings imply higher potential charge/discharge rates, making the need for this standardized information essential for safe charging, use, discharging and storage of LiPo batteries. Additionally, confusion with Burst and Constant C-ratings might confuse the user into thinking they’re using a battery of adequate C-rating as required by the application, only to find out that their purchase was based on a Burst rating instead of a Constant rating. Confusion of this sort can cause rapid overheating and dangerous fire hazards, and it has no place in ROAR competition.
***The above section will not be enforced until the beginning of the Winter 2011/Fall 2012 electric racing season (Beginning October 1, 2011). This should provide manufacturers and retailers sufficient time to comply with these requirements.
ROAR makes no inference as to the burst ratings. Manufacturers are welcome to include any additional information beyond the basic requirements outlined above. The required information is essential, however, in determining if a LiPo battery is sufficient for its application, and in determining safe charge/discharge parameters for each battery. It simply MUST be provided.
8.3.1.5.2 Any indication that the original manufacturer-applied label has been changed or tampered with will make the LiPo battery pack illegal. Aftermarket wraps/decals MUST NOT replace the original label. Should the original label be removed, the product will be ruled an unapproved product which could subject the racer to disqualification.
8.3.1.6 If protested, it is the driver’s responsibility to prove the legality of his battery(s).
8.3.1.7 Batteries may not be recharged or changed during a standard length race. Batteries may only be changed during an Endurance race.
8.3.1.8 Unless otherwise specified in the class requirements, a maximum of a 2s 7.4v LiPo battery is permitted in any vehicle motor power pack used in ROAR-sanctioned competition.
8.3.1.9 Drivers are responsible for the proper disposal of batteries that are no longer useable. No batteries should be discarded in ordinary trash containers, and may not be abandoned at race sites. It is recommended that tracks promote safety and non-pollution by providing an approved disposal container for unusable batteries.
8.3.1.10 Running Change to Cell: Manufacturers that make a running change without re-submitting the item for Lab review will forfeit the approval of that product, and possibly all related products from the manufacturer for a period of time to be determined by ROAR. A new component (especially a different composition of cell) will need to be submitted for inspection/approval. The LiPo Approval Inspection includes specifications our Race Management Teams can confirm in the field. If during the race inspections, a pack appears outside the original parameters, the Racer/User could be subject to disqualification for using an altered product. Deliberate attempts to use products that are not approved may result in a disqualification of no more than one year for one or all of a manufacturer’s related products, at the discretion of the ROAR President and the Executive Committee.
8.3.2 Lithium Polymer Batteries (Li-Poly):
8.3.2.1 Lithium Polymer battery packs may be used to power electric racing cars if a Certification of Compliance has been received and accepted by ROAR from the manufacturers of the battery packs. The Certification of Compliance indicates that the Lithium Polymer cells internal to the battery packs have been tested in accordance with UN T1-T8, the United Nations Recommendations on the Transport of Dangerous Goods, Manual of Test and Criteria (ST/SG/AC.10.11/Rev.4) and passed the acceptance criteria. Certification of Compliance to these test requirements and acceptance criteria shall be provided by the Original Manufacturer of the batteries. The Certification of Compliance will apply to all Lithium-Polymer products from the Original Manufacturer and provided on a one time basis. The Certification of Compliance can be sent directly to ROAR by the Original Manufacturer or supplied to ROAR by the US based distributor of the batteries. A reseller seeking secondary approval must also provide ROAR a Statement of Origin identifying the original manufacturer of the cells used in the battery pack
8.3.2.2 Li-Poly battery packs must have a hard, protective case that surrounds the cell(s) in the racing application. A factory-encased hard shell pack is mandated for race durability reasons that stem from the vulnerability of LiPo cells to physical damage. Any physical distortion, denting or puncture to the cells may cause either an immediate or long term safety risk. A hard-cased pack reduces this risk significantly by protecting the cells from crash damage, battery ejection, and general wear and tear. ROAR defines the “hard case” as a case made of ABS or similar type material. The case shall consist of two (2) halves with each half being constructed from a single mold that is not easily pliable and retains it shape without any exterior or interior support. Both the top and bottom sections of the case must be secured together by glue, double-sided tape or heat seal with a label across the seam stating “ROAR Approved” in such a manner that separation of the case to remove or replace the cells will destroy the case and/or label and render it unusable in competition. The case must be installed by the manufacturer or distributor; no user installed cases are acceptable. The case will protect the cells from damage on all sides and will completely cover all cells having only openings for wire connections. Any modification to the factory approved hard case will make the pack ineligible for participation in ROAR events. Approved batteries will be required to have a label stating “ROAR Approved” across the seam. ROAR will have a grandfather clause until Jan 2009 for all approved cells at competition on the Label rule.
8.3.2.3 LiPo/LiFe case maximum dimensions:
8.3.2.3.1 The maximum 1s 3.7v brick/stick case:
Length: 93mm
Width: 47mm
Height: 18.5mm
8.3.2.3.2 The maximum 1s 3.7v saddle case:
Length:93mm to be measured as two packs end to end as a maximum
Width: 46mm
Height: 23mm
8.3.2.3.3 The maximum 2s 7.4v brick/stick case::
Length: 139mm
Width: 47mm
Height: 25.1mm
8.3.2.3.4 The maximum 2s 7.4v saddle case:
Length: 139mm to be measured as two packs end to end as a maximum
Width: 47mm
Height: 25.1mm
8.3.2.3.5 The maximum 3s 11.1v or 4s 14.8v brick/stick case :
Length: 165 mm
Width: 52mm
Height: 52mm
8.3.2.4 The battery pack shall have leads extending from the case for the positive and negative electrical connections using wire of adequate size to handle discharge rates acceptable to racing applications. Alternatively, the case shall have external connection points for these wires clearly marked positive and negative so the user can apply the lead wires. Markings on the case are required stating the rated voltage, capacity, and C-rating of the battery. The distributor or reseller’s name and/or logo shall be easily readable on the case. Individual cells used in the construction of the battery shall be rated at 3.7v nominal. A 1s 3.7v nominal battery pack shall be 1 cell wired in series, a 2s 7.4v nominal battery pack shall be 2 cells in series, a 3s 11.1v nominal battery pack shall be 3 cells in series and a 4s 14.8v nominal battery pack shall be 4 cells in series. Multiple cells in parallel may be used.
8.3.2.5 Li-Poly Battery Charging and Discharging
8.3.2.5.1 Li-poly battery packs must be charged with chargers capable of the industry standard CC/CV (Constant Current/Constant Voltage) charge profile. No other charge profiles are permitted.
8.3.2.5.2 Li-Poly battery maximum charge voltage.
• 1s Li-Poly batteries may be charged to a maximum of 4.25v.
• 2s Li-Poly batteries may be charged to a maximum of 8.50v.
• 3s Li-Poly batteries may be charged to a maximum of 12.75v
• 4s Li-poly batteries may be charged to a maximum of 17.0v.
• 2S LiFe batteries may be charged to a maximum of 7.40v.
• There will be no allowances for overages.
8.3.2.5.3 Li-Poly battery maximum charge rate shall be 1C. C= charge amp rate unless specifically authorized by the manufacturer to charge at a different rate. Charge amp rate = mAh capacity/1000=X amps.
mAh Capacity 1C
3200mAh 3.2A
3300mAh 3.3A
3400mAh 3.4A
3600mAh 3.6A
3800mAh 3.8A
4000mAh 4.0A
4200mAh 4.2A
4600mAh 4.6A
4800mAh 4.8A
5000mAh 5.0A
5200mAh 5.2A
8.3.2.5.4 The maximum temperature of a charged battery will be checked prior to each run, to not exceed 100°F (37.8°C), or ambient temperature + 5-percent, whichever is greater. The use of a battery warmer is permitted, but it may never exceed 100°F (37.8°C). Preheating of batteries is not permitted in ambient temperatures above 100°F (37.8°C).
8.3.2.5.5 Batteries must be charged with chargers that have balance ports, using only the balance mode for charging, or an acceptable alternative demonstrated to the satisfaction of the President and/or Technical Director. Charging without balance mode and without a balancing harness is not permitted. Simply connecting the harness and not using the balance mode is cause for disqualification. Only 1S 1P batteries may be charged without balancing, as it’s only one cell. Any packs consisting of 2P and/or 2S will require balanced charging or approved alternatives.
Balance charging ensures that each cell within the pack charges individually to full capacity. Non-balanced charging may inadvertently overcharge one cell, and undercharge the other. Under these conditions, the risk for battery failure is greater, or at least you will suffer from reduced performance.
8.3.2.5.6 The use of cooling device and or freeze sprays of any type to cool a li-poly battery is strictly prohibited.
8.3.2.5.7 Overcharging/Overheating, or practices that may result in the aforementioned, are defined as but not limited to the following:
• Charging of a li-poly battery with a charge profile other than CC/CV (i.e. NiCd/NiMH)
• Charging at a charge rate higher than 1C (in lieu of the manufacturer’s recommended charge rate)
• Charged battery voltage exceeding the max charge voltage per 8.3.2.5.2.
• Heating of the LiPo battery beyond the maximum allowable temperature, or the use of cooling devices to cool an overheated battery per 8.3.2.5.4., 8.3.2.5.5. and 8.3.2.5.6.
8.3.2.5.8 All LiPo batteries must be charged or discharged inside a “Lipo Sack” or similar fire mitigation device proven to withstand a minimum of a 8.4v 5000mAh for 2s, or 14.8v 5000 mAh for 4s packs. Simultaneous charging or discharging of LiPo battery packs requires a separate LiPo sack for each battery.
8.3.2.6 ROAR Impact/Drop Test:
8.3.2.6.1 The cells of the battery pack shall experience no loss of mass, no leakage, no venting, no rapid disassembly, and no rise in temperature. The case shall not splinter or shatter in a manner that would create shrapnel and potentially puncture the cell inside.
8.3.2.6.2 The fully charged battery pack shall be dropped from a height of 5 feet to a flat concrete floor. The battery pack shall land flat on the floor during the drop.
8.3.2.8.2 A 0.1 Ohm resistance shall be applied to a fully charged battery pack at room temperature (70 deg F +/-10). The test is concluded when the temperature of the battery pack returns to within10 deg of room temperature.
8.3.2.10 General Information About Li-Poly Batteries:
8.3.2.10.1 A LiPo battery pack can be damaged in many ways. The damage is cumulative and cannot be reversed. These rules provide the safest operation and longest pack life. Going outside these rules may result in a dangerous pack failure.
• Do not over discharge Lithium Polymer battery packs, and use a Proper ESC that features a lipo-specific voltage cutoff feature. Some newer ESCs give you the option to set a cutoff voltage, and some do not. Use the battery manufacturer’s recommended safe voltage cutoff.
• The maximum safe temperature of a Lithium Polymer pack is 140 degrees F.
• Only charge Lithium Polymer packs with a charger that is specifically compatible with LiPo batteries.
• Lithium Polymer packs that will not be run for more than a month or two, should be stored approximately half charged. Do not store them fully charged and do not store them fully discharged (6.0v or less) or damage will occur.
• External Thermal Damage – Temperatures above 60 deg C or 176 deg F are considered extremely dangerous for LiPo batteries. The thermal volatility is directly related to the cell chemistry used by the manufacturer.
• Overcharge – Lithium Polymer cells are extremely intolerant of an overcharge condition. It can consistently damage the cell(s) and create a fire risk.
• Over discharge – over discharging can destroy a cell. Don’t discharge a battery below its recommended voltage level, or store you cells completely discharged. It is strongly recommended that you disconnect the battery from all electronics since most have a small current drain even in the “off” position.
• External Short Circuit – Lithium Polymer batteries can deliver extreme amounts of current. In the case of a short circuit (positive lead touches negative lead), the rapid and powerful current drain will cause the battery to overheat with an extreme risk of fire.
• Internal Short Circuit – this is mostly caused by contaminants getting into the cell at the cell manufacturing level. Contaminants can poke through the separator over time causing an internal short. In most cases, this will cause the cell to expand (puff up). In extreme cases, this may be enough to ignite the cell. Every time you charge a cell with a micro short, the cell will expand about five-percent in thickness. Batteries with a visible bulge in the casing should be considered damaged and should not be used in competition. Contact the battery manufacturer to determine the best method of neutralizing the battery for disposal. NEVER discard a charged battery, damaged or not.
• External Mechanical Damage – A lithium polymer battery is made up of 20-30 layers of a very thin sheet copper anode, a thin plastic separator and a thin aluminum cathode. The vacuum sealed aluminum pouch keeps even pressure on the anode/cathode pairs. Even a small dent that results from a dropped tool can create a micro-short in an unprotected pack. This short will create heat that will cause the cell(s) to expand and develop into a possible fire hazard. This is why ROAR requires hard cases, which greatly minimize the chance of external mechanical damage to the cells.
